复发-缓解型多发性硬化患者脑白质的多体素磁共振波谱成像特征

Multi-voxel Magnetic Resonance Spectroscopy Imaging Features of White Brain Matter in Patients with Relapsing-remitting Multiple Sclerosis

目的探讨复发-缓解型多发性硬化(RRMS)患者大脑白质微观结构发生的异常改变的多体素磁共振波谱成像(MRS)特征。资料与方法对17例RRMS患者与21名健康志愿者(对照组)行全脑常规MRI及多体素MRS,在MRI结构像所显示的正常表现白质(NAWM)区域内选取相应的体素检测N-乙酰天冬氨酸(NAA)/肌酸(Cr)、胆碱(Cho)/NAA和Cho/Cr比值。结果全局分析结果显示,RRMS组脑内NAWM区域内的NAA/Cr低于对照组(P<0.001),而RRMS组Cho/NAA高于对照组(P<0.001),两组Cho/Cr差异无统计学意义(P>0.05)。RRMS组在额叶、顶叶及顶-枕叶3个NAWM子区内NAA/Cr较对照组分别下降11%、23%和12%(P<0.001),顶叶区NAA/Cr的下降程度高于其他2个被检子区(P<0.05)。结论RRMS患者白质内轴突结构的损伤或破坏并非仅局限于MRI图像上显示的局灶性病变。代谢物水平的微观异常改变在顶叶NAWM区内较额叶及顶-枕叶NAWM区内敏感性更高。

Purpose To investigate the abnormal micro-structure changes of the brain white matter in patients with relapsing-remitting multiple sclerosis(RRMS)in multi-voxel magnetic resonance spectroscopy imaging.Materials and Methods Whole brain routine MRI and multi-voxel MRS imaging were performed in 17 RRMS patients and 21 healthy volunteers.Corresponding voxels were selected to detect the ratios between N-acetylaspartate(NAA)and creatine(Cr),choline(Cho)and NAA,Cho and Cr in the normal-appearing white matter(NAWM)region manifested on the MRI images.Results The global analysis showed that NAA/Cr ratio in the NAWM region in the RRMS group was lower than that in the control group(P<0.001)while the Cho/NAA ratio in the RRMS group was higher than that in the control group(P<0.001).No significant difference in the Cho/Cr ratio was found between the two groups(P>0.05).The NAA/Cr ratios in the three NAWM sub-regions(the frontal,parietal and apical-occipital)in the RRMS group were decreased by 11%,23%and 12%,respectively,compared with that in the control group(P<0.001).The decreasing degree of NAA/Cr ratio in parietal NAWM was obviously higher than that in the other two NAWM sub-regions(P<0.05).Conclusion The damage or destruction of axon structures in the white matter of RRMS patients is not limited to the focal lesions shown on MRI images.The sensitivity of the microscopic abnormal changes in metabolite levels in the parietal NAWM region is higher than that in the frontal and occipital-occipital NAWM regions.